This invention relates to a magnetic head manufacturing method and a magnetic head used in a magnetic disc device.
The recording density upon recording information on magnetic recording media are under progress. For HDD (hard disc drive), a system having the recording density as high as 5 to 7 Gbit/inch2 has actually been brought into practice for HDD (hard disc drive), and higher densities are still being demanded. An answer to this demand is to realize a magnetic head with xe2x80x9cnarrow tracksxe2x80x9d whose recording track width is not larger than 1 xcexcm.
Also for thin-film magnetic head incorporating recording and reproducing functions, various structures have been proposed toward realization of narrow tracks.
For example, Japanese Patent Laid-Open Publication No. H10-214407 discloses a record/reproduce integral thin-film magnetic head having the structure shown in FIG. 42.
FIG. 42 is an elevational view which shows the medium facing surface of the record/reproduce integral thin-film magnetic head. Formed on a substrate (not shown) is a lower magnetic shield layer 1 made of a soft-magnetic material. Formed on the lower magnetic shield 1 is a magnetoresistance effect film (MR film) via a lower reproducing magnetic gap 2 made of a non-magnetic insulating material. A pair of leads 4 are connected to opposite ends of the MR film 3. These elements constitute a MR element portion 5. Formed on the MR element portion 5 is an upper reproducing gap 6 made of a non-magnetic insulating material. Further formed thereon is an upper magnetic shield layer 7 made of the same material as that of the lower magnetic shield layer 1. These elements constitutes a shield type MR head 8 which functions as a reproducing head.
On the reproducing head made up of the shield type MR head 8, a recording head made up of an inductive-type thin-film magnetic head 9. These elements constitutes a record/reproduce integral magnetic head 10.
The lower write pole of the inductive-type thin-film magnetic head 9 is composed of the soft-magnetic layer forming the upper magnetic shield layer 7 on the shield type MR head 8. That is, the upper magnetic shield layer 7 also functions as the lower write pole of the recording head. On the lower write pole 7 commonly used as the upper magnetic shield layer (hereinbelow simply called lower write pole), a write magnetic gap 12 made of a non-magnetic material is provided. The lower write pole 7 has a projection as a magnetic pole tip portion (gap facing portion) 11. The top surface of the projecting lower tip portion 11 for contact with the write magnetic gap 12 has the width corresponding to the record track width Tw. The write magnetic gap 12 is formed to extend along the contour of the lower write pole having the projecting lower write pole tip portion 11. A non-magnetic material layer 13 is formed to sandwich the lower write pole tip portion (projection) 11 including the write magnetic gap 12 from track width directions. The non-magnetic material layer 13 has a recess 14 positionally aligned with the projection 1. The recess 14 is buried with the magnetic material which constitutes the upper magnetic tip portion 16 of the upper write pole 15. The upper write pole tip portion 16 projects toward the write magnetic gap 12. On the back side (remoter from the viewer of FIG. 42) of the upper write pole 15 including the magnetic pole tip portion 16 buried in the recess 14, a coil (not shown) buried in an insulating layer is provided on the non-magnetic material layer 13. These components explained above make up the record/reproduce integral magnetic head 10.
In magnetic heads having this type of structure, the tip portion 11 of the lower write pole and the tip portion 16 of the upper write pole opposed to each other via the write magnetic gap 12 are equal in width. Therefore, it is free from the problem which occurs upon making narrower tracks in magnetic heads in which the upper write pole and the lower write pole are different in width, that it, the problem of offsets of record bit lines at edges due to a leak magnetic field from the record track side and reproduction writing.
In the record/reproduce integral magnetic head shown in FIG. 42, the top end of the lower magnetic head 7 is previously shaped to project, the non-magnetic material layer 13 is formed to have a recess above the projection, and a magnetic material is buried in the recess and used as the upper write pole 15.
Although various methods such as plating and collimation sputtering are considered usable for making the upper write pole 15 to bury the recess, plating is much more advantageous than others because of the low process cost and its actual results. However, in order to bury and make the upper write pole 15 without any empty spaces, it is necessary to previously provide a conductive layer in the recess, which is used as a plating electrode film.
For this purpose, it would be possible to use the method which makes the write magnetic gap 12 by a conductive material and buries in one recess the lower write pole tip portion 11, write magnetic gap 12 and upper write pole tip portion 16 altogether by plating. However, if a conductive film is used as the write magnetic gap 12, an overcurrent loss occurs, and the magnetic property of the magnetic head degrades.
Additionally, in the case where the width of the upper write pole tip portion 16 is narrower than the width of the top portion (supplemental magnetic pole 15B) of the upper write pole 15 as shown in FIG. 42, intensity of the magnetic field which leaks from corners E made by the upper write-pole 15 on the side nearer to the magnetic gap is liable to increase, and causes the problem that, during writing of a signal into the recording medium, it is written to an adjacent track, or information on an adjacent track is erased.
On the other hand, when the upper write pole 15 shown in FIG. 42 is made, U.S. Pat. No. 5,283,942, among others, teaches first forming a layer mainly forming the upper write pole tip portion 16 and thereafter making the remainder layer mainly used as the supplemental magnetic pole 15B. In this case, the interface where the layer first made and the remainder layer connect (which lies in the level shown by the broken line A in FIG. 42) comes inside the upper write pole tip portion 16 or approximately lies on the boundary between the upper write pole tip portion 16 and the supplemental magnetic pole 15B.
However, along the interface between the layer previously made and the remainder layer, there often remain a deteriorated layer made on the surface of the previously stacked layer by oxidation and layers of non-magnetic material such as base layer required for making the remainder layer, although they are thin in thickness. Therefore, the interface between the previously stacked layer and the remainder layer results in lying on the boundary between the upper write pole tip portion 16 and the supplemental magnetic pole 15B, to which is the magnetic flux is concentrated more, and this portion behaves as a pseudo boundary and causes leakage of the magnetic flux and deterioration of the magnetic property thereby.
This invention has been made remarking these problems.
The first object of the invention is to provide a manufacturing method of a magnetic head, which is effective for manufacturing a record/reproduce integral magnetic head having a head structure suitable for narrower tracks and a higher line recording density, by previously shaping an upper portion of a lower recording magnetic pole to project from the other part so as to bury and form an upper write pole in a recess of a non-magnetic material layer formed above the projection in a self-alignment fashion, and ensures that the upper write pole be made with a good buried property and that the magnetic head be excellent in magnetic property as well.
The second object of the invention is to provide a manufacturing method of a magnetic head which can remove the problems such as undesirable writing into an adjacent track or undesirable erasure of information from an adjacent track during writing of a signal onto a recording medium, which were inevitable when narrowing only the tip of the upper write pole to meet the need for narrower tracks, by reducing the intensity of the magnetic field which leaks from corner portions on one side of an upper portion of the upper write pole (supplemental magnetic pole) nearer to a magnetic gap.
The third object of the invention is to provide a magnetic head capable of reducing the magnetic field which leaks from a pseudo magnetic gap appearing at boundaries of respective layers when the magnetic pole is formed in two or more divisional steps, and a manufacturing method of this magnetic head.
A method for manufacturing a magnetic head which includes a lower write pole having a projection, an upper write pole having a projection opposed to the projection of the lower write pole, and a magnetic gap interposed between the projection of the upper write pole and the projection of the lower write pole, comprising the steps of forming the magnetic gap on the projection of the lower write pole, forming a first non-magnetic material layer stacked on the lower write pole and having on its surface a first recess opposed to the projection of the lower write pole in positional alignment therewith, forming a tip portion of the projection of the upper write pole by burying a magnetic material in the first recess, forming a second non-magnetic material layer on the first non-magnetic material layer, the second non-magnetic material layer including a second recess opening wider than the first recess and having inner wall surfaces curved, and forming the other part of the upper write pole by burying a magnetic material in the second recess.
A method for manufacturing a magnetic head which includes a lower write pole having a projection, an upper write pole having a projection opposed to the projection of the lower write pole, and a magnetic gap interposed between the projection of the upper write pole and the projection of the lower write pole, comprising the steps of forming the magnetic gap on the projection of the lower write pole, forming a non-magnetic material layer on the lower write pole, the non-magnetic material layer having a projection on its top surface in positional alignment with the projection of the lower write pole, forming a mask layer on the non-magnetic material layer, the mask layer having an opening in which the top surface of the projection of the non-magnetic material layer is exposed, forming a first recess in the non-magnetic material layer by isotropically etching the non-magnetic material layer through the opening of the mask layer, forming a second recess down from the bottom of the curved recess by anisotropically etching the non-magnetic material layer through the opening of the mask layer, and forming the projection of the upper write pole by burying a magnetic material in the tapered recess and the curved recess.
A method for manufacturing a magnetic head which includes a lower write pole having a projection, an upper write pole having a projection opposed to the projection of the lower write pole, and a magnetic gap interposed between the projection of the upper write pole and the projection of the lower write pole, comprising the steps of forming the magnetic gap on the projection of the lower write pole, forming a first non-magnetic material layer stacked on the lower write pole and having on its top surface a first recess in positional alignment with the projection of the lower write pole, forming a plugging material different from the first non-magnetic material layer in the first recess, forming a second multi-layered structure on the first non-magnetic material layer, forming on the second non-magnetic material layer a mask layer having an opening in positional alignment with the projection of the lower write pole, forming a second recess by isotropically etching the second non-magnetic material layer through the opening of the mask layer until exposing the plugging material, removing the plugging material from the second recess, and forming the upper write pole by burying a magnetic material in the first recess and the second recess.
A method for manufacturing a magnetic head which includes a lower write pole having a projection, an upper write pole having a projection opposed to the projection of the lower write pole, and a magnetic gap interposed between the projection of the upper write pole and the projection of the upper write pole, comprising the steps of forming the magnetic gap on the projection of the lower write pole, forming a first non-magnetic material layer stacked on the lower write pole and having a first recess on its surface in positional alignment with the projection of the lower write pole, forming an umbrella-shaped mask which includes a foot portion buried in the first recess, a stem portion extending upward from the first non-magnetic material layer, and an overhang portion at a distance from the first non-magnetic material layer, forming a non-magnetic material to make of the first non-magnetic material layer a second non-magnetic material layer having a second recess formed under the overhang portion of the mask, removing the mask, and forming the projection of the upper write pole by burying a magnetic material in the first recess and the second recess.
A method for manufacturing a magnetic head which includes a lower write pole having a projection, an upper write pole having a projection opposed to the projection of the lower write pole, and a magnetic gap interposed between the projection of the upper write pole and the projection of the upper write pole, comprising the steps of forming the magnetic gap on the projection of the lower write pole, forming a first non-magnetic material layer stacked on the lower write pole and having a first recess on its surface in positional alignment with the projection of the lower write pole, forming a plugging material on the first non-magnetic material layer, inviting self-contraction of the plugging material to make a plugging body which has a foot portion buried in the first recess and a round portion spreading out above the foot portion, forming a non-magnetic material to make on the first non-magnetic material layer a second non-magnetic material layer having a second recess made under the liquid drop portion of the plugging body, removing the plugging body, and forming the projection of the upper write pole by burying a magnetic material in the recess of the multi-layered structure and the curved recess.
The present invention having the above-summarized structures has the following effects.
According to the invention, when a record/reproduce integral magnetic head is manufactured by previously shaping an upper part of a lower recording magnetic pole into a projection and making an upper write pole by burying it inside a non-magnetic-material layer stacked on the projection, it is possible to make out the upper write pole with a good buried property by plating and obtain a magnetic head excellent in magnetic property and realizing narrower tracks.
In addition, according to the invention, in the case where only the tip end of the upper write pole is narrowed to meet narrower tracks, it is possible to reduce the leakage of the magnetic intensity from corner portions nearer to the magnetic gap of the upper part of the upper write pole (supplemental magnetic pole portion) and remove the problems of undesirable writing onto an adjacent track or erasure of information from an adjacent track during writing of a signal onto a recording medium.
Furthermore, according to the invention, when the magnetic pole is made in two or more separate steps, it is possible to reduce the leakage of the magnetic field from pseudo gaps produced along boundaries of respective layers and thereby provide a magnetic head excellent in recording property.